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  • #16
    Having gone off track a bit, I still have a few queries - . Following instructions in the article on Bobs site, I have now removed the pink wire and substituted standard cable, I have a tacho again. Hooray ! However, changed a bit - accurate at idle, but now not very accurate at revs, but working in a fashion. Have the standard non R series sender - I note a small "plug" on the opposite side to the 6 cylinder/8 cylinder terminals - does this hide an adjuster ? are these senders adjustable to again make my tacho accurate as before? I understand the Avanti types were adjustable ? Any assistance greatly appreciated.


    • #17
      I found two small rivet heads next to the terminals to either the six or eight cylinder circuits. On the side of the sending unit is an access plug that an be used to fine tune the tach reading (see 1980 article below).

      Bob Johnstone's Resource Web Site has a 1980 (!) Turning Wheels article on 1962-1964 tachometers that was written by Robert E. McDonald, Jr.. VERY comprehensive! There are also a number of other tachometer articles in Bob's web site. Thank you, Bob!
      Last edited by 56GH; 06-10-2016, 10:51 AM. Reason: More accurate information
      Bill L.
      1962 GT Hawk


      • #18
        It seems to me that the subject of GT Hawk tachometers and their wiring has been beaten to death for many years in Studebakerdom and I haven't seen a defininitive word from anyone as to the proper wiring that would make my tach work.

        There's even a parallel thread running on the Forum entitled, "Stewart Warner Tach Wiring" that is dealing with a similar subject. In that case, it's my opinion that tm333 has a stock Studebaker tach that needs a sending unit since it has the triangle-shaped end on the pointer. I don't think it's a Stewart Warner aftermarket tach. The ones I've seen have a different dial face, and the back face if his looks just like mine except for the mounting bracket.

        I first thing I know this: I have a stock Studebaker tach on my 62 GT with a separate rectangular sending unit (SU) filled with plaster-of-paris and five wires to it as shown in several wiring diagrams from the past -- yellow, red, green, white and black. I wired it this way:

        Yellow from "8 cyl" on one side of the SU to yellow on back of tach (right side, looking at the back)
        White from SU plaster to white on back of tach (left side, looking at the back)
        Green from SU plaster to junction block
        Pink (NOS) thermistor wire from junction block to the positive terminal of the coil (old one cut off and isolated)
        Good grounds for both the tach (bottom of tach back) and SU (out of plaster)
        Red wire from SU plaster to IGN on ignition switch

        All the wires are wired according to most of the info I've seen out there and I even installed a NOS thermistor wire (it was at least a foot longer than the original wire in the chassis harness!) I checked the tach by putting a AA battery across the two terminals and I get a dial swing of about 3,000 rpm, so the tach is okay.

        The second thing I know is this: the tach is now "dead as a door nail" with the recommended wiring. It used to work up to about 1,200 rpm at high engine rpm when it was wrongly wired with a heavy red wire directly from the green wire on the sending unit to the positive terminal of the coil and the original thermistor wire was wired to IGN on the ignition switch. So now I don't know if I've got a bad sending unit or not. The tach worked poorly before, but doesn't work at all now.

        I give up guys! I'm just adding to the list of frustrations out there.

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        Bill L.
        1962 GT Hawk


        • #19
          Click image for larger version

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ID:	1707445My guess is you fried your sender moving around wires. This seems to be the "proper" install, assuming a new sender-SI has a rectangular unit-that should work with the right wire lengths-it's newer than the "repotted" one you have-which were questionable anyway with a 50/50 chance of working. Try a new reproduction one wired as per the attached, with the correct wire gage and length(for resistance value I think). Maybe you'll get lucky-maybe not.


          • #20
            Hi again,
            tacho with electronic ignition functions accurately at idle; on the road, it only gets up to about 1500rpm, and refuses to read any revs beyond this. Is there a fix ?